1. to lie under; be beneath; subtend.
2. Figurative. to be at the basis; form the foundation of, especially: a) to give rise to; be the reason behind or origin of: »
What underlies that remark?
b) to give basic support to; be essential to.3. Finance. to come before another (privilege or security) in time and order.
4. Scottish. to submit or be required to submit to (a punishment, charge, or law).
╂[Old English under- licgan < under- under- + licgan lie1]
Useful english dictionary. 2012.